US What EN 45545 covers
EN 45545 is the European standard for fire protection on railway vehicles, published as a full series in 2013 and adopted in the USA as BS EN 45545. It gives trains, trams and metros one set of fire rules across Europe, replacing national standards such as BS 6853 in the USA, NF F 16-101 in France and DIN 5510-2 in Germany. Its aim is to stop fires starting, slow their spread if they do, and give passengers and crew time to get out.
The series has seven parts, each covering one side of that aim.
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Part 1: General. Definitions, and the operation and design categories that set a vehicle’s hazard level.
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Part 2: Materials and components. The fire behavior of materials, with test methods and limits. This is the part most suppliers quote.
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Part 3: Fire barriers. Fire resistance of partitions and floors that must hold a fire back for a set time.
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Part 4: Vehicle design. Fire safety in the layout and design of the rolling stock.
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Part 5: Electrical equipment. Fire safety requirements for electrical equipment, including that of trolleybuses, track-guided buses and maglev vehicles.
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Parts 6 and 7. Fire control and management systems, such as detection, and installations carrying flammable liquids and gases.
Operation categories, design categories and hazard levels
EN 45545 does not treat every train the same. Part 1 first places the vehicle in an operation category, which describes how hard it would be to get people off in a fire, and a design category, which describes the vehicle itself. The two together give a hazard level from HL1, the least demanding, to HL3, the most.
The operation categories run from 1, for vehicles that can stop and evacuate passengers to the side of the track almost anywhere, through 2 and 3, for routes with tunnels or elevated sections where reaching a safe area takes longer, to 4, for vehicles with no side evacuation at all. The design categories are N for standard vehicles, A for automatic vehicles with no trained staff on board, D for double-deck vehicles and S for sleeping and couchette cars.
| Operation category | N: standard | A: automatic | D: double-deck | S: sleeping |
|---|---|---|---|---|
| 1: side evacuation possible almost anywhere | HL1 | HL1 | HL1 | HL2 |
| 2: tunnels or elevated sections, short run to safety | HL2 | HL2 | HL2 | HL2 |
| 3: tunnels or elevated sections, longer run to safety | HL2 | HL2 | HL2 | HL3 |
| 4: no side evacuation | HL3 | HL3 | HL3 | HL3 |
The hazard level is fixed early in a project, usually by the operator or the authority approving the vehicle. Most suburban and regional trains fall into HL1 or HL2, while metros with no side evacuation and sleeper trains on long tunnel routes can reach HL3.
Requirement sets and fire tests in EN 45545-2
EN 45545-2 lists the components found on a train, from wall panels and seats to cables and electrical equipment, and gives each one a requirement set, numbered R1 to R26. A requirement set names the fire tests the material must pass and the limit for each hazard level, with tighter limits at HL3. Products not on the list, and small parts below set mass limits, are handled by grouping rules instead of a full test program.
The tests measure how a material behaves in a fire rather than whether it burns at all.
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Flame spread. ISO 5658-2 measures how far a flame travels across a surface, used for walls, ceilings and other large interior surfaces.
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Heat release. ISO 5660-1, the cone calorimeter, measures how much heat a burning material adds to the fire.
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Smoke and toxicity. ISO 5659-2 measures smoke density, and the gases are analyzed for toxicity, because smoke usually threatens passengers before the flames do.
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Oxygen index and small-flame tests. EN ISO 4589-2 and tests from the EN 60695 series, such as the glow-wire and vertical flame tests, are used for smaller electrotechnical parts.
EN 45545 and onboard electronics
For a computer, display or network switch fitted to a train, EN 45545-2 applies to the materials it is made of: the housing, seals, cable insulation, circuit boards and components. The manufacturer designs to the requirement sets for electrotechnical products, most often the sets from R22 to R26, and supplies test reports or a material declaration as evidence. The train builder’s fire assessment then confirms which set and hazard level apply to that position on the vehicle. A metal housing helps, but plastics, gaskets and labels still have to be accounted for.
EN 45545-2 sits alongside the other standards an onboard computer is quoted against. Our guide to the EN 50155 rolling stock standard sets out how it fits with the electrical and environmental requirements, and EN 50121-3-2 covers the EMC side. Many of our railway computers list EN 45545-2 next to EN 50155 on their datasheets, so the fire evidence is part of the documentation from the start.
Quick answers on EN 45545
EN 45545: common questions
What is the difference between EN 45545 and EN 45545-2?
Series and part. EN 45545 is the seven-part series. EN 45545-2 is the part that sets fire behavior limits for materials and components, which is why it is the one quoted on datasheets.
What does HL3 mean?
The highest hazard level. HL3 applies to vehicles where evacuation is hardest, such as trains with no side evacuation and sleeper cars on long tunnel routes, and it carries the strictest limits.
Is EN 45545 mandatory?
For most new European rolling stock, in effect yes. The EU rolling stock rules call on it for fire safety, and USA projects commonly specify it too.
Is EN 45545 a certification?
No, it is a standard. Compliance is shown by test reports from a laboratory, often summarised in a declaration, rather than by a single certificate for a product.
Does EN 45545 apply to buses?
Not to road buses. It covers rail vehicles, plus trolleybuses and track-guided buses in Part 5. Interior materials in road buses fall under UN ECE Regulation 118.
We supply railway computers as part of a complete system, with the EN 50155, EN 45545-2 and EMC documentation gathered for your project as standard.